A new research, published on Monday in the Archives of Neurology, has revealed that hereditary factors are very much influential among the people with Alzheimer's disease. The study at the University of Washington in Seattle has affirmed that the people born to the parents suffering from Alzheimer's have much higher risks of developing the disease.

Studying 111 families in which both parents were diagnosed with Alzheimer's disease, the research has assessed the higher risks of developing the disease among their offsprings.

Involving the parents who had 297 children who lived into adulthood, the study has found that of the 98 men and women who were at least 70 years old, 41 of them - about 42 % - developed Alzheimer's disease. It has found that their offspring had a 22.6 % chance of developing the condition compared with the estimated 6 to 13 % chance in the population as a whole.

According to the research, the people whose parents both have the disease are more likely to develop Alzheimer's earlier in life, at around 66 years of age. One of the main authors of the research, Dr. Thomas Bird said, "That's greater than you would expect in the general population in that age group."

Generally, the risk of the disease begins to rise at about age 65, with the number of people developing the disease doubling every five years beyond that.

Bird said, "I think it confirms that there's a strong genetic component in the disease and that's not a surprise."

According to Bird, a gene, known as ApoE, is generally agreed among researchers to be causing the disease, but there likely are many more causes. Involved in making a substance in the body, the ApoE gene helps to carry cholesterol in the bloodstream and the gene seems to influence the age of onset of Alzheimer's.

According to the head of research at the Alzheimer's Society, Dr Susanne Sorensen, the study is an important addition to comprehend the causes of the disease that includes symptoms such as loss of memory and problems with speech and understanding.

However, scientists haven’t yet been able to fully understand the causes of Alzheimer's disease, although genetics plays an important role. There is no cure.

Dr Susanne Sorensen said, "Scientists have been aware for some time that the genes we inherit from our parents may partly determine whether we will develop specific diseases. However, the role of genetics in the development of dementia is still not fully understood. We are still learning what causes Alzheimer's disease and other forms of dementia."

Alzheimer's disease is the most common form of dementia among the elderly people. It is the condition that affects about 400,000 people in Britain.